Circuit interrupter with damper body to reduce speed of moving terminal having a cross slide latch

ABSTRACT

After initial arc drawing movement the rodlike terminal of a high-voltage alternating-current power fuse driven by a spring and gas pressure has its speed reduced by encountering a damper body which is normally latched in a stationary position until it is unlatched on impact by the terminal. A cross-slide latch is employed to hold the damper body stationary in a fuse housing for release on impact by the terminal.

United States Patent [72] Inventor flenryW.Scherer Niles,lll.

211 AppLNo. 104,552 221 Filed 3,267,235 2,247,704 7/1941 Triplett 2,087,774 7/1937 Triplett........................

Jan. 7,1971 {45] Patented Dec.2l,l97l

[73] Assignee S & C Electric Company Chicago, Primary Examiner-Bernard A. Gilheany Assistant Examiner-Dewitt M. Morgan 54] CIRCUIT INTERRUPTER WITH DAMPER BODY TO REDUCE SPEED OF MOVING TERMINAL HAVING A CROSS SLIDE LATCH ABSTRACT: After initial are drawing movement the rodlike 6 chin", 8 terminal of a high-voltage alternating-current power fuse 52 us. 337/215 drive" by a spring and gas Pressure has Speed. reduced by 511 1m. encwmering a damP" which is normally latched a stationary position until it is unlatched on impact by the terminal. A cross-slide latch is employed to hold the damper body stationary in a fuse housing for release on impact by the terminal.

HOlh 85/36, HOlh 85/42 [50] Field of 337/168, 171,174,175, 219, 275, 282, 285

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' SHEET 1 [1F 5 PATENTEU DECZI m sum 2 OF 5 PATENTEU me: 1911 SHEET BF 5 7 0 j 2 J yRJ w J J CIRCUIT INTERRUPTER WITH DAMPER BODY TO REDUCE SPEED OF MOVING TERMINAL HAVING A CROSS SLIDE LATCH This invention relates, generally, to high-voltage alternating-current power fuses and it has particular relation to such fuses of the dropout type disclosed in Barta U.S. Pat. No. 3,267,235, issued Aug. 16, 1966, although it is not limited to use in this particular fuse construction or in a dropout fuse.

This invention relates to the fuse construction disclosed in Schmunk application, Ser. No. l04,55l, filed Jan. 7, I97], and assigned to the assignee of this application.

In the drawings:

FIG. I is a view, in side elevation, of a typical mounting arrangement for hinge and latch assemblies for the dropout fuse disclosed herein. 6

FIG. 2 is a view, in side elevation, of a dropout fuse provided with trunnion and fuse tube release assembliesarranged for cooperating with the hinge and latch assemblies of the mounting shown in FIG. 1.

FIGS. 3a, 3b, 3c and 3d positioned one above the other with FIG. 3a at the bottom show a vertical longitudinal cross-sectional view of the fuse shown in FIG. 2, the showing here at an enlarged scale.

FIG. 4 is perspective view of the cross-slide latch that is employed for holding the damper body against movement.

FIG. 5 is'a view similar to portions of FIGS. 3b and 3c and shows the rodlike terminal having been released and the damper body unlatched but not coupled.

FIG. 6 is a view similar to FIG. 5 showing the damper body unlatched and coupled for conjoint movement to the rodlike terminal.

FIG. 7 is a view at an enlarged scale, partly in side elevation and partly in section, of the upper end of the dropout fuse, the showing being in the unlatched position of the latch release tube prior to permitting the fuse to swing to the open or dropped out position.

In FIG. I reference character 10 designates, generally, a mounting for an alternating current circuit interrupter of the fuse type and particularly of the dropout fuse type. However, it will be understood that the present invention can be employed in a fuse of the nondropout type. The mounting 10 includes a channel base 11 which is provided with lower and upper insulators l2 and 13 near its ends. The lower insulator 12 carries a hinge assembly that is indicated, generally, at 14 while the upper insulator 13 carries a latch assembly that is indicated, generally at 15. In FIG. 2 there is indicated, generally at 16 a dropout fuse which includes a fuse housing, indicated generally at 17, a trunnion assembly, indicated generally at 18, at its lower end and a latch release assembly, indicated generally at 19, at its upper end. The hinge assembly 14 is provided with trunnion receiving slots 22 which are arranged to receive trunnions 23 that extend from opposite sides of the trunnion assembly 18 for the purpose of pivotally mounting the dropout fuse 16. A bifurcated latch 24 is pivotally mounted at 25 on the latch assembly and it includes a roller 26 for latching engagement with a roller 27 that is carried by a hook 28 which extends laterally from a metallic fitting 29 which forms a part of the fuse housing 17 and is located near its upper end. The roller 27 is arranged to underlie the roller 26 for the purpose of holding the dropout fuse 16 in the operative upright position. Nose portions 30 are provided on the forward end of the bifurcated latch 24 for engaging the upper side of a radial flange 31 which is located at the lower end of a latch release tube 32. When the latch release tube 32 is moved upwardly, for example, by a pivoted pull ring 33, the latch 24 is lifted to disengage the roller 26 from the roller 27 and permit the fuse 16 to swing about the trunnions 23 to the open circuit position.

In FIG. 3a it will be observed that a lower terminal or ferrule 37 is located at the lower end of the fuse housing 17. It is connected to the hinge assembly 14 through the trunnion assembly 18 to provide a circuit therebetween. The terminal or ferrule 37 is connected by an inner metallic ring 38 and sleeve 38' to a metallic bridge 39 which extends across the lower discharge end of the fuse housing 17. A terminal rod 40 extends through the metallic bridge 39 and is secured in position thereon by nuts 41. The terminal rod 40 constitutes a stationary arcing terminal. The lower end of the fuse housing 17 is closed by a closure disc 42 which is blown out on operation of the fuse. A fusible element 43 is connected to the upper end of the terminal rod 40. The fusible element 43 includes a fuse wire 44 and a strain wire 45 the upper ends of which are connected to the lower end of a rodlike terminal 46. The rodlike terminal 46 is movable upwardly through a bore 47 that is formed in cakes 48 of a suitable arc extinguishing material, such as boric acid. It will be understood that, when the fusible element 43 blows on flow therethrough of current in excess of a predetermined current, the rodlike terminal 46 moves upwardly through the bore 47 from the surface of which an arc extinguishing medium is evolved. Incident to the drawing of the arc and upward movement of the rodlike terminal 46 is the application thereto of gas pressure which acts to drive the rodlike terminal 46 upwardly in addition to the force exerted thereon by a spring to be described.

FIG. 3b shows the details of construction of the fuse 16 immediately above those illustrated in FIG. 3a. Here it will be observed that the rodlike terminal 46 extends upwardly through additional cakes 48 of arc extinguishing material and that it is provided with an enlarged contact section 51 having contact fingers 52 in engagement therewith. The contact fingers 52 extend upwardly from a contact fitting 53 which is secured to a contact sleeve 54 that is located at the lower end of and is connected to an upwardly extending tubular contact terminal 55. As shown in FIG. 30 the upper end of the tubular contact terminal 55 is connected to a contact fitting 56 which forms a part of the fuse housing 1.7 and is connected directly to the metallic fitting 29 to complete a circuit therethrough to the latch assembly 15. A coil compression spring 57, FIG. 30, is interposed between the upper side of the contact sleeve 54 and the under side of a rod end fitting 58 which is secured to the upper end of the rodlike terminal 46. In this manner the rodlike terminal 46 is biased upwardly for movement through the bore 47, the spring force being restrained by the fusible element 43 as long as it remains intact.

As pointed out hereinbefore it is desirable to limit the speed of the rodlike terminal 46 after blowing of the fusible element 43 and on movement of the rodlike terminal 46 to a predetermined position under the combined influences of the gas pressure, previously referred to, and the force exerted by the coil compression spring 57. In accordance with this invention a guide tube 61 is secured to the metallic fitting 29 and extends upwardly therefrom for receiving therein a metallic damper body 62. When released, the metallic damper body 62 is freely.

slidable upwardly through the guide tube 61. Under normal operating conditions before the fusible element 43 is blown it is desirable that the damper body 62 be held against any movement. The reason for this is to avoid any displacement of it when the fuse 16 is subjected to shocks incident to shipping, handling, etc. For this purpose the damper body 62 is provided with a transverse slot 63 in which a metallic cross-slide latch 64 is located. This latch is shown in detail in FIG. 4. It has a latch pin extension 65 which is arranged to extend into a latch opening 66 that is located, in part, in the upper end of the contact terminal 55 and in part in the contact fitting 56. It will be understood that the latch opening 66 is located in the fuse housing 17 for receiving the latch pin extension 65 to prevent endwise movement of the damper body 62. A leaf spring 67 is employed for biasing the cross-slide latch 64 to the latched position. The leaf spring 67 is secured at 68 to the damper body 62. Its distal end 69 bears against one end of the cross-slide latch 64 to hold it in the latched position shown in FIG. 30. The cross-slide latch 64 is provided with a central circular opening 70 having a tapered entrance opening 71.

It is necessary to unlatch the damper body 62 when the rodlike terminal 46 has moved upwardly through a predetermined extent so that subsequently the two can be coupled together for continued conjoint movement at a reduced speed. For this purpose a tapered section 72 of a metallic ram pin 73 is arranged to enter the entrance opening 71 and to move into the opening 70 in the cross-slide latch 64 as illustrated in FIG. 5. This action shifts the cross-slide latch 64 from the latched position and withdraws the latch pin extension 65 from the latch opening 66. The damper body 62 then is free to move upwardly through the guide tube 61 conjointly with the rodlike terminal 46. The ram pin 73 has a cylindrical section 74 for fully entering the cylindrical opening 70 in the crossslide latch 64 and holding it in the unlatched position. The damper body 62 has a central opening 75 opposite a button head 76 on the ram pin 73 against which a coil compression spring 77-.in the opening 75 reacts to bias the ram pin 73 downwardly to the latching position against a shoulder 78 provided by a coupler ring 81 to be described.

It is important that the rodlike terminal 46 be securely coupled to the damper body 62 and that there is no bounce to the coupling. For this purpose coupling means is employed and is secured to the lower end of the damper body 62 by screws one of which is indicated at 80 in FIG. 3c. The screws 80 extend through a metallic coupler ring 81 which has a central opening 82 and a tapered entrance opening 83. A reduced diameter impact end 84 of the ram pin 73 extends downwardly through the central opening 82 and projects therebelow. The lower end of the impact end 84 of the ram pin 73 is arranged to be engaged by an upper end 85, FIG. 3b, of a metallic coupling tip 86 which actually is an extension of the rodlike terminal 46. At its lower end the coupling tip 86 has an extension 87 that is threaded at 88 into the upper end of the rod end fitting 58. It will be understood that the metallic coupling tip 86 constitutes a unitary construction with the rodlike terminal 46. The coupling tip 86 has a beveled upper end 89 and a tapered section 90 for entering the central opening 82 and tapered entrance opening 83 in the metallic coupler ring 81.

FIG. shows the position of the rodlike terminal 46 and parts movable therewith just after the metallic ram pin 73 has been engaged and moved upwardly sufflciently far to unlatch the cross-slide latch 64 by moving the latch pin extension 65 out of the latch opening 66. Here the beveled end 89 of the metallic coupling tip 86 is shown as extending through the central opening 82 in the metallic coupler ring 81. As yet the damper body 62 has not been moved upwardly.

FIG. 6 shows the subsequent relationship between the rodlike terminal 46 and the damper body 62 when they are moving upward conjointly under the combined influences of the coil compression spring 57 and the gas pressure that is applied to the rodlike terminal 46. Here it will be observed that the tapered section 90 has been driven into the central opening 82 in the metallic coupler ring 81. A substantial part of the kinetic energy of the moving rodlike terminal 86 is dissipated in the deformation of the metallic coupler ring 81 and in the elongation of the tapered section 90. This absorption of kinetic energy is in addition to the kinetic energy that is dissipated in accelerating the damper body 62 in moving upwardly. There is a corresponding reduction in the speed of upward movement of the rodlike terminal 46 and a corresponding reduction in the length of the gap between the upper end of the terminal rod 40, FIG. 3a, and the retracting lower end of the rodlike terminal 46.

The rodlike terminal 46 and the damper body 62 continue their upward movement until finally the upper end of the damper body 62 engages the underside of a closure cap 94, FIGS. 3d and 7 which is located at the upper end of the latch release tube 32. The latch release tube 32 is moved upwardly to shift the radial flange 31 from the broken line position shown in FIG. 7 to the full line position there shown for lifting the latch 24 to the released position. The fuse 16 then swings downwardly about the trunnions 23 to the open circuit positron.

In FIG. 3c it will be observed that the latch release tube 32 is telescoped over the guide tube 61 which directs the upward movement of the damper body 62. The latch release tube 32 is biased downwardly by a cor compression spring which reacts between the underside of a washer 96 that bears against a shoulder 97 on the guide tube 61 and the upper end of a tubular upwardly extending extension of the radial flange 31 which is secured to the lower end of the latch release tube 32. That extension is indicated at 98. The downward movement of the latch release tube 32 is limited by a rain shield 99. A sleeve overlies the lower portion of the extension 98 and the upper portion of the rain shield 99 to limit the entrance of moisture therebetween.

What is claimed as new is:

1. An alternating-current circuit interrupter comprising: a housing having a latch opening, a body of arc extinguishing material in said housing having a bore from which an arc extinguishing gas is evolved due to the heat of an arc, a stationary terminal on said housing at one end of said bore, a rodlike terminal movable in said bore, spring means in said housing biasing said rodlike terminal for movement through said bore, fusible means interconnecting said terminals and adapted to blow on flow therethrough of predetermined alternating current whereupon an arc is drawn between said terminals and said rodlike terminal is moved through said bore by pressure or gas evolved from said bore and by said spring and is extinguished after one or more current zeros, a damper body movableendwise of said bore in said housing and arranged to be engaged by said rodlike terminal after it has been moved in a predetermined distance on blowing of said fusible means, cross-slide latch means slidable on said damper body and having an opening therethrough and a laterally extending latch pin for entering said latch opening in said housing, and ram pin means slidable endwise of said damper body through said opening-in said cross-slide latch means and adapted to be impacted by said rodlike terminal for withdrawing said latch pin from said latch opening to release said damper body and effect conjoint movement of said rodlike terminal and said damper body and corresponding reduction in the speed of said rodlike terminal with a consequent decrease in its movement during successive half cycles of the alternating current.

2. The circuit interrupter according to claim 1 wherein: spring means bias said rarn pin means away from said crossslide latch means and spring means bias said cross-slide. means to hold said latch pin in said latch opening.

3. The circuit interrupter according to claim 2 wherein: said spring means biasing said ram pin means comprises a coil compression spring located in a longitudinal opening in said damper body, and said spring means biasing said cross-slide latch means is a leaf spring secured at one end to said damper body and reacting at its distal end against said cross-slide latch means.

4. The circuit interrupter according to claim 1 wherein: said opening in said cross-slide latch means has a tapered entrance, and said ram pin means has an inclined section for engaging said tapered entrance to displace said cross-slide latch means from latching position.

5. The circuit interrupter according to claim 1 wherein: said damper body has an opening extending centrally longitudinally thereof from the end toward said rodlike terminal for slidably receiving said rarn pin means, said cross-slide latch means is slidable transversely of said central opening in said damper body and said opening therein registers with said central opening, a coupler ring is secured to said damper body with the opening therein registering with said central opening and provides a shoulder for said ram pin means, and a coil compression spring in said central opening biases said ram pin means against said shoulder.

6. The circuit interrupter according to claim 5 wherein: said ram pin means has a reduced diameter end portion extending through said coupler ring for receiving the impact of said rodlike terminal. 

1. An alternating-current circuit interrupter comprising: a housing having a latch opening, a body of arc extinguishing material in said housing having a bore from which an arc extinguishing gas is evolved due to the heat of an arc, a stationary terminal on said housing at one end of said bore, a rodlike terminal movable in said bore, spring means in said housing biasing said rodlike terminal for movement through said bore, fusible means interconnecting said terminals and adapted to blow on flow therethrough of predetermined alternating current whereupon an arc is drawn between said terminals and said rodlike terminal is moved through said bore by pressure or gas evolved from said bore and by said spring and is extinguished after one or more current zeros, a damper body movable endwise of said bore in said housing and arranged to be engaged by said rodlike terminal after it has been moved in a predetermined distance on blowing of said fusible means, cross-slide latch means slidable on said damper body and having an opening therethrough and a laterally extending latch pin for entering said latch opening in said housing, and ram pin means slidable endwise of said damper body through said opening in said cross-slide latch means and adapted to be impacted by said rodlike terminal for withdrawing said latch pin from said latch opening to release said damper body and effect conjoint movement of said rodlike terminal and said damper body and corresponding reduction in the speed of said rodlike terminal with a consEquent decrease in its movement during successive half cycles of the alternating current.
 2. The circuit interrupter according to claim 1 wherein: spring means bias said ram pin means away from said cross-slide latch means and spring means bias said cross-slide means to hold said latch pin in said latch opening.
 3. The circuit interrupter according to claim 2 wherein: said spring means biasing said ram pin means comprises a coil compression spring located in a longitudinal opening in said damper body, and said spring means biasing said cross-slide latch means is a leaf spring secured at one end to said damper body and reacting at its distal end against said cross-slide latch means.
 4. The circuit interrupter according to claim 1 wherein: said opening in said cross-slide latch means has a tapered entrance, and said ram pin means has an inclined section for engaging said tapered entrance to displace said cross-slide latch means from latching position.
 5. The circuit interrupter according to claim 1 wherein: said damper body has an opening extending centrally longitudinally thereof from the end toward said rodlike terminal for slidably receiving said ram pin means, said cross-slide latch means is slidable transversely of said central opening in said damper body and said opening therein registers with said central opening, a coupler ring is secured to said damper body with the opening therein registering with said central opening and provides a shoulder for said ram pin means, and a coil compression spring in said central opening biases said ram pin means against said shoulder.
 6. The circuit interrupter according to claim 5 wherein: said ram pin means has a reduced diameter end portion extending through said coupler ring for receiving the impact of said rodlike terminal. 